1. Field of the Invention
The present invention relates to a projection exposure mask acceptance decision system and a projection exposure mask acceptance decision method for a projection exposure mask used in manufacturing process for semiconductor device, a method for manufacturing a semiconductor device, and a computer program product.
2. Description of Related Art
The manufacturing process for semiconductor device includes a pattern formation process (lithography process) for forming various patterns on a semiconductor wafer. In a lithography process, a projection exposure mask or the like is used. By measuring the dimensions of the patterns formed by the lithography process, an average value and an in-plane uniformity of the pattern dimensions are obtained. An exposure characteristic deterioration quantity of the used projection exposure mask is calculated on the basis of the determined average value and in-plane uniformity. An exposure characteristic deterioration quantity is, for example, an exposure margin deterioration quantity. Depending on whether a projection exposure mask satisfies an exposure characteristic deterioration quantity required for a lithography process, it is judged whether the projection exposure mask is acceptable or not (Jpn. Pat. Appln. KOKAI Publication No. 2002-72440).
In a projection exposure mask, there are a plurality of quality assurance objects such as a line width (CD), a phase shift, transmittance, and the like. A first exposure characteristic deterioration quantity S1 caused by deviations from the respective average values of a plurality of quality assurance objects is obtained by a simple sum of the respective exposure characteristic deterioration quantities of the plurality of quality assurance objects. A second exposure characteristic deterioration quantity S2 caused by respective dispersion of a plurality of quality assurance objects is obtained by calculating a root sum square of the respective exposure characteristic deterioration quantities of the plurality of quality assurance objects. Then, an entire exposure characteristic deterioration quantity ΔELa of a projection exposure mask is obtained by a sum of the first exposure characteristic deterioration quantity S1 and the second exposure characteristic deterioration quantity S2.